Electron beam controlling system



m 1956 A. w. FRIEND ELECTRON BEAM CONTROLLING SYSTEM 3 Sheets-Sheet 1Filed May 26, 1950 INVENTOR June 19, 1956 A. w. FRIEND 2,751,519

ELECTRON BEAM CONTROLLING SYSTEM Filed May 26, 1950 3 Sheets-Sheet 3 '1I! z I I I I 4 Q I vvv 5 5 0 553 0 5.

' EDECFRON BEAM CON TROELING SYSIEM Albert W. Eriend, Brinceton, N. 'J.,assignor .to Radio Jllo poratlon .ojfAmei-ica, a, .corp,oration ofDelaware -Application' May 26, 1950,!Serial No. 164,444 .24 .Claims.,(Cl. 315-913) ,Ihis inventionrelates to .systems fOIUCQIliIQlllIlgJhCelectron beams .,of cathode ,ray :tubes. .Althcugh not necessar y :limte thereto, the .-i.nvent n -.-re te t 36 tems; for.efiectingconvergenceof .a plurality, i -electron beam components at all-points in a predetermined p e.

One of .the=-cornmon fuses of.cathode raystnbes;is ;for the reproductionoftelevisionvimages. .Moreparticularly, in .color television systems,there have .been deviscd cathode-ray, tubes .capable of reproducing:imagessubstam tiallyjn apluralitylof their natural component-colors. :Atypical tube. -of. this character, :Which-has been.- s l 'iccssfullynsed,.formnasubjectsmatter of a copendingll. ;S.;applica- .tionof.Alfred'C. Schroeder, :Serialp-No. .7.30-,-.637, =file d .Eebruary 24,1947, now "Patent No. -2,5.95,5,-48 issued May G, 1.952,;and titled fPicture Reproducing-Apparatus? In general, such .a tube is provided-with.aluminescent screen .madec-uprof a multiplicity of phosphor-gareas dsub-elemental dimensions ;.arranged in .groups substantiallyofelementalsize. "Each of:.the difllerent phosphors of these groups is.capableo'f. emitting lightof adilferent one of the component imagecolors whenuexcitedrbyran electron .-beam. "Such a-itube'is providedwithian-raper- .tured masking; electrode mounted between the screensand.aillurality :of,elec.tr.on.=guns. iTheseguns are arranged with respect:to: one another. so. thatathey direct :beams -of electrons through :theapertures of rthe masking electrode from different angles.so-.thatpredetermined ones of the United States Patent l sclifl rm point pa r m.,gi. udina Patented June 1 9, 1 955 mployedlt is an object of thisinvention to efiect substantial convergence -at all points in a.predetermined plane ,pf 21 rlur litytc' elect i s eam .a mrans t sm neftam hodej ayt ube Anothei' object of the invention is to, etfectsubstantial convergence at all pointsin .a predetermined plane of ,a,plura lity of electron -,beams emanating respectively from a plurality,of electron gunsmountedin. spaced relationship to .the centraIraxisrofaa. cathodemay tube.

,IStill ,anothenobject, of the inventionis ..to efiechsub- ;stantialconvergence .at .all .points .of -a predetermined plane of;.aplutalitypfelectron.beanncomponentshaving ,pat hsmpaced from ,the,central ,axis .of Va cathodetay. .tube and. allnernanatingtfromassingle electron gnnlocated substantially .on said .centrahtube axis.

e A .iurth eruobject, of ,the invention .is ..to..e fiect ,,elec tro-.staticallysubstantial convergence of a plurality. of electron beamswhichhavepaths spaced .fromthe ,central axis .of ,a. cathode...ray tubeand which are electnomagnetically doflectedovenatarget electrode.

A still -,further, .object oftheinventionis to.cilectclectrnmagnetically s ubstantial convergence .of .a plurality of,elec'tron beam components whichhave paths spaced from sub-elementalphosphorarcas may' be-selectively-excited.

'Another tube-.of the :samegeneral character -asthat disclosed in theSchroeder applicationv referred -to,-forrns the subjectmatter of acopending Uns. application of Russell R. Law, Serial No. 165,552, filedJune 1,4950 and titled Color Television. Ihe chief difference betweenthe Law .and :Shroeder-tube'sfis in the use of a singleelectron gun inthe Law tube. This prejerably ismountedalong the'central axis of thetube. The single electron beam which is produced "by the gun issubjected to a particular :type of deflection hymeans of which itisrotated about the central tube axis. It is seem therefore, that, bysuitably controlling an electrohibeamp l e character described, theapertured masking electrode and the luminescent screen may be approachedfrom fferent angles by electron beam components substantially in, thesame manner as effected in thenSchroeder tube Th expr ss e ec r .beam.c,, mp en ca sed inthisspec fic tion is ten ed t v t .typc. .9119nhqrrexc tina le t oni en rg p uce b$'.. ,iu l s PlUIMHYi A ECH Q un ,Tiss e syrmas' l m .tiru li v em la n s q r 'thout, ceram cs- 9 the scopeof this-inuention.

In ,either the single or multiple .electron .gun type .of.color..,television. lcinescope .it :is necessary vto deflecnall of.thetelectron ,beam components .over. ;the ;.target ,electrqde in .amanner .tori orrn' .a.-.conven'tio nal television raster. -Eu t erm0 tes r b1 th arhi :.d fiec qn .Qf h :difififflfltz elect n beam componen s.426, ,efie tedw ;;;a s ngl .tdefi c o ys m flTh o ev .rre eu t .the=central axisof acathode ray tube and, whichare,electromagneticallytdefiected over. the. target. electrode.

In accordance With the invention thecathqde ray tube s m uvi e w t alectron-opti a .sy t m-adi em 10 rthe paths, of ,a plurality of electronbeam components ahe'adpfihe point at .Which they,a re,,su.bjected.to.,tl 1e influence. ,of ,the deflection .;system eby -vvhich t l 1etarget elec od is can e e e s -qpti .systs n ta ably n r ize t f e t c nr en e s sc nhsam ssmpsmem ta tra s-i .l r an fifth tar e els trod Theen rgiZaIion of th .e ec rq zQptic .system is ,varied as a, function ofthevar'iable eneggization of the deflectingsystem. Specifically m -order.to control. convergence pf ,theelectron, beam components in aevertigalsense and to alesser extent in ua horizontal s ensylhe energization ofthe electronoptical system is .variedas,a function of the verticaldeflection. Similarly the enercita i f li elec ronti yste i .vari d a afunction of the h orizontal. electron beam, deflection ..i n or er tocontrol beam convergence in aghorizontal sense, and to a lesser extentinme VerticaLsense.

.lThael ctwn beam d flec nand the ram t m op tical convergence systems,may. be eitherselectrpmag- ,netic ,o f electrostatic. ,For example,.in. .one .of .the,.,i1lus- ,trated embodiments of the,.invention,..tl1ebeam deflection system is. electromagnetic andlheelectron-optical,system .is electrostatic. -In another illustrated.embodimennof rthe .inyention .both deflection .and convergence systems.are slec mmas fi The, novel features thatare considered characteristic-or' ghis inyention -are set forth with particularity in f th appendedclaims. The invention itself,ghovyever both as to -;its eorganizationand :method of operation .as well as additional objects r and featuresthereof .will 'best-rbemnderstood from the following description, takenin conjunction with the accompanying drawings.

In the drawings:

Figure 1 is a graphical representation of one phase of the problem ofeffecting convergence of a plurality of electron beam components at allpoints in the plane of a target electrode;

Figure 2 is a graphical representation of another phase of the electronbeam convergence problem;

Figure 3 is an illustration of one form of electron optical system whichmay be embodied in a system according to this invention;

Figure 4 is a circuit diagram of a television receiver embodying a formof the invention employed in conjunction with a cathode ray tube havinga plurality of electron guns and an electrostatic dynamicelectron-optical beam convergence system; and

Figure 5 is a circuit diagram of a television receiver embodying theinvention in another form which uses a cathode ray tube having a singleelectron gun and an electromagnetic electron-optical system foreffecting convergence of a spinning type of electron beam at all pointsin a plane of a target electrode.

Before this invention can be fully appreciated, the problem which is tobe solved by it must be understood. For this purpose, reference will bemade first to Figure 1 of the drawings. The geometrical relationshipsbetween a pair of electron beam components are illustrated in thisfigure. The angular disposition of the beam components relative to oneanother and to the axis and target electrode of a cathode ray tube aregreatly exaggerated in this figure. By such means, the criticalrelationship between the electron beam components may be more clearlyshown. It is assumed that the electron beam components considered hereoriginate at points disposed at equal distances above and below alongitudinal axis of the tube. The representations in this figure are ineffect projections of the paths of the electron beam components into avertical plane. However, for ease of reference in the following portionsof this description, the lines representing the path proiections of thebeam components will be referred to as the electron beams themselves.

The central longitudinal axis of the cathode ray tube is represented bythe line 11. The upper and lower electron beam components 12 and 13respectively approach the axis 11 from substantially equal angles a. Theangles a will be referred to herein as the convergence angles of theelectron beam components. The line 14 represents the plane in whichdeflection of the electron beam components is assumed to be effected. Inthe absence of any deflection of the electron beam components 12 and 13they converge at a point 15 on the axis 11 of the tube in the plane of atarget electrode 16. It will be noted that the convergence point 15 islocated substantially centrally in a vertical sense on the targetelectrode.

It will be considered that, for color television purposes, the targetelectrode 16 is provided with a plurality of apertures, one of which islocated at the point 15. Both of the undeflected electron beamcomponents 12 and 13 will pass through the aperture at an angle a withthe axis 11. As a consequence, the beam components approach aluminescent screen (not shown in this figure) from different angles inorder to excite selectively the phosphor areas thereof. It is necessary,however, for the successful operation of a device of this character thatthe electron beam components be made to converge at all other points inthe plane of the target electrode 16. It will be demonstrated presentlythat, in order to effect such convergence, facilities in addition to theusual electron beam-deflecting system are required.

In considering this phase of the problem of effecting convergence of aplurality of electron beam components, it will be considered thatdeflection of the electron beams 12' and 13 is to'be made verticallysubstantially in the plane of the drawing. Assume that, under theinfluence of a suitable deflecting system effective substantially in theplane indicated by the line 14, each of the electron beam components 12and 13 is deflected upwardly through an angle +15. The deflected beamsthen follow the broken lines 12a and 13a. It also may be considered thatthe axis 11 is deflected through the angle +b and therefore takes theposition indicated by the broken line 11a. It will be seen that the convergence angle a between the deflected beam components 12a and 13a,respectively, and the deflected axis 11a remains unchanged. However, thepoint 17 at which the deflected beam component 12a intersects thedeflected axis 11a is considerably short of the plane of the targetelectrode 16. It also does not coincide with the point 18 at which thedeflected beam component 13a intersects the deflected axis 11a. As aresult, the deflected beams 12a and 13a will not pass through the sameaper ture in the target electrode 16. Consequently, two differentelemental areas of the luminescent screen will be excited by the beams12a and 13a.

When the electron beam components 12 and 13 are deflected downwardlythrough an angle b along the dot-dash lines 12b and 13b they intersect adeflected axis 11b at different points, neither of which is in the planeof the target electrode 16. In this case, the deflected beam component12b intersects the deflected axis 11b at the point 19 which is spacedfrom a plane of the target electrode 16 a distance substantially equalto the spacing of the intersection of point 18 of the upwardly deflectedbeam component 13a and the axis 11a. Similarly, the downwardly deflectedbeam component 13b intersects the axis 11b at a point 20. This point islocated substantially at the same distance short of the target electrodeas the point 17 representing the intersection of the upwardly deflectedbeam component 12a and the axis 11a.

The are or curve 21 represents the locus of the intersections of theelectron beam component 12 and the effective axis 11 of the tube.Similarly, the are or curve 22 is the locus of the intersections of thebeam component 13 and the effective tube axis. These curves graphicallyrepresent the dynamic control required by an electron-optical system toeffect substantial convere gence of the electron beam components at allpoints in the plane of a target electrode. For small values of theconvergence angle a, the curve 22 may be expressed by the equation S isthe distance between the plane of deflection and target electrode 16. Seis the distance between the plane of deflection 14 and the intersectionof the deflected beam component 13a and the tube axis 11a in theabsencev of any dynamic beam convergence control. The same equation,with the sign of angle a reversed, represents the curve 21.

It may be readily determined, by inspection of Figure 1, that thesolution to the problem of effecting convergence of a plurality ofelectron beam components at all points in a television or other rastermay not be completely solved by providing a target electrode of aparticular curvature; In the present case, a compromise target electrodeconfiguration would be in the form of a curve 23 lying substantiallymidway between the arcs 21 and 22. The curve 23 represents the locus ofthe convergence points of the electron beams 12 and 13 In practice, thecurves 21 and 22 may be made to approach closely the shape of curve 23by minimizing the convergence angles a. Nevertheless, such a targetelectrode configuration is not particularly adapted'for use in atelevision image reproducing device. In devices of such character it isdesirable to provide the target electrodes with shapes which are as flatas possible.

' electron guns.

the function of effecting convergence of the electron beam scope capableof reproducing an image in three of its component colors. Onerepresentative example of a tri-color kinescope of the kind suitable foruse in conjunction with the present invention is shown in the previouslymentioned Schroeder Patent No. 2,595,548. The Schroeder tube, and alsothe tube 46, is provided with three electron guns and a luminescentscreen. The screen is selectively excited to produce differently coloredlight by electron beam components approaching it from differentdirections.

The tube 46 is provided with electron guns 47, 48 and 49. It will beunderstood that the electron guns preferably are symmetrically disposedwith respect to one another and also relative to the central axis of thetube,

such as in the case of the electron guns 36, 37, and 38 of Figure 3.Also the tube 46 is provided with a luminescent screen 51 which issubstantially flat as shown.

In the particular tube illustrated, the screen 51 is mounted on atransparent plate which is supported in back of, and somewhat spacedfrom,'the end wall 52 of the tube. It is to be understood that such astructural arrangement is not intended to be limiting. Alternatively, itmay be desirable in some instances to provide the luminescent screendirectly upon the inner surface of the end wall of the tube. In anycase, the luminescent screen consists of a multiplicity of groups ofphosphor areas or dots, each of sub-elemental dimensions capablerespectively of emitting light of different colors when excited byimpinging electrons. The groups of phosphor areas may be arranged in anydesired pattern such as clusters of small areas of circular, triangular,hexangular, or other configurations or the linear strips extending fromone side of the screen to the other.

The tube 46 also is provided with an apertured masking electrode 53mounted in back of, and in spaced relation to, the luminescent screen51. This electrode is provided with apertures conforming in shapesubstantially to the configuration of the phosphor groups. For example,in the case of substantially circular groups of phosphor areas, theapertures in the electrode 53 will be substantially circular. Oneaperture for each group of phosphors preferably is provided.

The color kinescope 46 also is provided with a deflecting system which,in the present case, is an electromagnetic yoke 54. The deflecting yokeis mounted in the usual manner about the outside of the neck portion ofthe kinescope.

The color kincscope also is provided, in accordance with this invention,with a dynamic electron-optical system located in the region between theelectron guns and the deflecting yoke. In the present form of theinvention,

this electron-optical system is electrostatic and includes a cylindricalanode member 55 surrounding the paths of the electron beam componentsemanating from the three In order for this electrode to performcomponents at substantially all points in a raster scanned at themasking electrode 53, it is necessary that the field produced by it andthe final anode wall coating 55, be varied suitably as a function ofboth the horizontal and vertical deflections of the beam components toform the raster.

Before describing the control circuits for the different electrodes ofthe color kinescope 46, a brief reference will be made tothe manner inwhich the electron beam components cooperate with the aperturedelectrode 53 to excite selectively the sub-elemental phosphor areas ofthe luminescent screen 51. Consider, for example, the excitation of thesubstantially central point of the screen 51. The electron gun 47 isactuated concurrently with the reception of the video signalrepresenting the red com- H ponent of this area'of the image. Theelectron beam component emanating from this gun follows a path which isindicated at 56 as it approaches the masking electrode 53.

above the central axis of the tube. Consequently,'this It is seen thatthe angle of approach is fromv beam component, after traversing theaperture of the electrode 53, impinges upon a red light-emittingphosphor area 57. Similarly, in concurrence with the reception of greenand blue video signals the electron guns 48 and 49, respectively, areactuated to produce electron beam components which approach theelectrode 53 from angles represented by the lines 58 and 59,respectively. As a consequence, the green and blue sub-elementalphosphor areas 61 and 62, respectively, are selectively excited.

The synchronizing signal channel 45 of the color televisionsignal-receiving system may be considered to include the usual apparatusincluding synchronizing signal separators and deflection generators. Thehorizontal and vertical deflection generators are coupled conventionallyto the deflecting yoke 54 for suitably varying its excitation to deflectthe beam components to form a television raster.

The apparatus included in the synchronizing signal channel 45 also isemployed to control the development of suitable voltages for impressionupon the dynamic electron-optical system including the anode 55. Forexample, short voltage pulses at the vertical deflection frequency maybe derived from the vertical deflection generator. These verticalfrequency pulses are impressed upon wave shaping apparatus 63. Thisapparatus serves to develop a sawtooth wave and a wave having asubstantially parabolic form, both having the vertical deflectionfrequency. The vertical frequency sawtooth wave is coupled by acapacitor 64 to a vertical convergence control voltage generator 65.Also the vertical frequency parabolic wave is coupled by a capacitor 66to the vertical convergence control voltage generator 65. This apparatusfunctions to combine the waves to produce a composite vertical frequencywave for impression upon the anode 55.

In a similar manner, a horizontal frequency sawtooth wave is derivedfrom the synchronizing signal channel 45 and is impressed upon ahorizontal convergence control voltage generator 67 by means of acoupling capacitor 68. Also, a horizontal frequency parabolic wave isimpressed upon the generator 67 by a coupling capacitor 69. A compositehorizontal frequency wave is produced by the generator 67 for impressionupon the anode 55.

The vertical frequency pulses may be derived from the output circuit ofthe vertical deflection generator. The horizontal frequency sawtoothvoltage may be obtained at the output circuit of the horizontal sawtoothoscillator. The horizontal frequency parabolic wave conveniently may bederived from the storage capacitor of the damperbooster forming part ofthe horizontal deflection system. A typical damper-booster of the typereferred to is disclosed in an article by A. W. Friend titled TelevisionDeflection Circuits, published at page 98 of the March 1947 RCA Review,vol. VIII, No. 1. sentative.

The outputs of the vertical and horizontal convergence control voltagegenerators and 67 respectively, are combined to produce a compositeconvergence control voltage which is impressed by means of a couplingcapacitor 71 upon the anode 55. The electric field produced by thisanode varies, therefore, in accordance with both horizontal and verticaldeflections of the electron beam components. Consequently, the beamcomponents may be made to converge substantially at all points of theraster scanned in the plane of the masking electrode 53.

Details of an illustrative embodiment of apparatus'for developing theelectron beam convergence control voltages also are shown in Figure 4.The wave-shaping apparatus 63 includes a resistive-capacitive networkconsisting of a series connection of resistors 72, 73 and 74 and a shuntcapacitor 75 to ground from the junction point between resistors 72 and73. This network is connected to thesynchronizing signal channel 45 forthe impression thereon of voltage pulses by which thereis Figure 19 isreprewinding lllrcfsa transformer .113.

:9 dettelepedsatthe junction point between the resistors 73 and -74 ;asubstantially saw-toothed voltage having .the irequency of the:yertical; deflection-=of the electron .beam components.

The wave-shaping apparatus 63 alsoeincludesa'resistivecapacitive-network consistingof a series connection ofresistors 76-and 77and shunt capacitors 78 and 79 :connected togroundsubstantiallyas .shown. The input teriminal gofthis network is coupledto the synchronizing ,signal channel -45. The output terminal of thenetwork is coupled-by-a capacitor 81 to the control grid of an electronarnplifier tube 82. A.- grid-leak resistor -83 is coupled from thecontrol grid-to the junction point between resistors 84 and 85connectedain series between athe'cathode -of the tube and ground. Theapparatus functions to prodncea substantially parabolic wave form atthe.junctionpointbetween resistors-84 and 85 at the vertical deflectionfrequency.

{Iihe vertical'convergence control voltage generator 65 includes aninput electron tube :86, to the control .grid of 'which theucouplingcapacitor .64 is connected. :Also, this circuit is provided with agrid-leak resistor..87 con- ;nected between-the control grid and thejunction point between-:a pairrof resistors .89 and '91 connectedinseries .-betweenethe cathode of the tube 86zand.ground. .Space currentfor the input tube isprovided from a source indicated at +13, through aload resistor 92 connected -to 1116 anode: of the tube.

.-A;-b alanced output circuit is. provided .for the tube .86.

'It ;comprises a series connection of substantially equal .resistors193and 94 which arecoupled respectively bya .capac itor -95 .to theanode ofthe tube and a capacitor :9,6 to-t;he cathode of the tube. The junction;point between the output circuit resistors is -grounded. The.terminaIs-oLtheoutput circuit resistors 93 and 94 are connectedtogether by a potentiometer .97. By suitably ad- -justing thepotentiometer :97, .the magnitude and polarity of the vertical sawtoothvoltage may be varied.

.?l.he vertical convergence control voltage generator 65 also includesan output electron tube 98. The ,control grid of the tube :98- isconnected as .shown to the-po- :tentiome ter .97. In this manneracomponent .of the verticalsawtooth wave is impressed .upon the tube 98.Thecontrol gridof this tube also is connected through-a resistor .99; toa variable point .011 a resistor .101 to which the .input coupling.capacitor,66.-isconnected. By .this means a .suitable component ;of thevparabolic .wave at the :vertical :defiecting frequency is impressed.upon the tube 9.8. Theca'thodeof this tube includes aself-biasingnetwork including a, resistor 10.2 and .a bypass capacitor 1.103. Spacecurrent for .the-tubeis supplied through a choke coil .104.

.Thexoutput circuitof the tube 98 includes the primary winding 105 :of atransformer 7106. This winding is coupledatotheanode of thetube .98 by acapacitor 107. The .transformer is provided with a secondary winding108, .one terminal of which is connected :to the .ungrounded sterminal.ofthe primary winding .105 :and the otherterrninal :of;. which isconnected to ,the horizontal voltage control generator 67.

The .-horizontal voltage generator 67 is substantially :similar in formto -the vertical. control generator 65. The.;chief .:=ditferences Ibetween the two generators ,are in the values of the circuit componentsrequired for thedifierent operating frequencies. Accordingly, .the de-"tails :of1the generator -;67 which are similar to those of thegenerator 65 willinot be specifically described.

.Thezinput tube 109 of the horizontal control voltage generator:671iscoupledbetween the synchronizing signal channel A5 and an:outputelectron .tube 111. This latter tube .alsozis connected to thesynchronizing signal channel for Ethe suitable combination of thesawtooth .and parabolicwavestat..the horizontal deflecting frequency.The output circuit of the tube 111 includesthe-primary This transformeralso has .a secondary Winding 114 havingone terminal connected to thesecondary .winding :108 of the-....\gertical control voltage generator,65. The other .tegninal of..thc :windinglltl is coup1e d;by-. ecapacitor 71 .to the dynamic -cotwer tnce controlanode. 55.

fl?\eference now will .be made. :to Figure 5 .of. the ,draw- .ings whichshows an. embodiment of this invention .used in conjunction twith acolorkinescope havingacingh electron-gun -for;providing the plurality.ofelectron beam components. The television receiver-in this form of"the invention includesa ,colorzkinescope v1:15. .ln general, this; tubeis 10f the same-character as the .colorrkinescope :46 of Figure 4.tltcomprises a-luminescentscreen 116 {and 33,11 -apcntured :rnaskingelectrode 117 similar to .the screen 51 and .electr0de53- of Figure .4.It also is. .pr.oygided.with a.;de flecting yoke 118 capable, whensuitably energized, to deflect the electron beam compqnentghdthhorizontally andvertically ;to scan a predeterminedpataternflorrrasteriat :the electrodes 116 and 117. Ihistub'e,

.however,; is -p1-fovided with a .single electron gun 119 .to

:Produoe;an electronwbeam which is modulated :in intensity in accordancewith received color video signals -by-meaus -0i'. a suitableconnectionto the *video signal channel-44. It .will be inndcrstood thatthe electron beam produced -by lthe gt1n;fll9,.also' mayabe keyed at thecolor-changing or, other suitable freguency in order to produce aplurality. of.;electroni=beagncomponents capable respectively .pfexciting the"luminescenbscreen 116 to produce thedifierentiinragecolors.

A IYP Gil56Xan1pl e,;of .a .-tube of this characterformstthe.subjcctumattemof the cepending U. S. applicationof RussellnR. Lawpreuiously referred to. in this typepofatuhe, the plurality of electronbeam components .by which selective gcolor exeitation of theluminescentscreen 'may be aeliected is; oduced "by-lactating or spinning the beamaboutthe;.coutrahor:o henpredetermined longitudinalaxis of theatube."AQC,Qflingly,-lh6 tube is providedswith a circular .idellection yoke1-2 1. The 'yoke is energized-by energydenived from aw-rotatingfield-generator-IZZ. The .energization :of the yokeg is suitable toproduce va rotating fieldin the path- 0f the electron beamso :that: thebeam is caused to continuously rotate about the axis of the :tube. *The-notatingfield generator 122-is controlled bysuitable.;swnals.zdeiivedafromthe synchronizing signal channeliE0l;-6X1IQP1, the control signals for-the rotating field generator 122may be they-horizontal syn- I chronizing apulses .xdBriYQ ai 3 m y c ing si separator,

'The deflectingyoke 21118:;is energizedin a conventional "manner bymeans of horizontal and yertical deflection generators I123.=which are-synchronized in the :usual :man- .ner .by suitable connections .to thesynchronizing-signal channel 'tS.

Also, conventionally provided with -the;.kinescope .115 .is .a-nragneticbeam convergencecoil .124. This coil may be conventionally energizedfrom a suitable :Powepsuply indicated as ra battery 125. :Avariable-resistor or rheostat 1 26 connected in :series between -the:.power;sup-

ply-1'25 and the coil 2124 serves tocontrol the magnitude of the coil.energization.

Also, this form of the :invention thedynamicconvergence .Dflth6:plurality of electron beam components is controlled by a coil 12-7.Asin the other formant the invention previously described,thedynamic-electron- :optical system: comprising the .coil 127 i isenergized v variably by an electriccurrent which varies .as afunctionofthe horizontal andvertical deflection of theelectron beam componentsover the luminescent vscreenof the tube. .In this case, the coil 127. iscoupled *to a .control voltage generator 128. Nerticah-and =horizontalsynchronizing pulses 'are impressed-upon the input circuit ofmagenqerator 128 -by means including capacitors 129 and .1-31.

'The :operation of the ;color-kinescope 115. in'this 1 bodiment 1 of;the invention ,is, substantially isimilargto zthat described inconjunction-with Iheapparatus of .-.FjguPe .4.

The mean difference in the two modes of operation is in the derivationof the plurality of electron beam components by which the luminescentscreens are excited. Instead of having a beam component available forapproach to the screen from any one of three different angles as in thepreceding case, the spinning action of the single electron beam providessuch components at predetermined successive time intervals. As indicatedin the Law application referred to, the rotating electron beam may bekeyed so that it is effective only when it is coming from predeterminedpoints from which it may approach the target electrode from desiredangles. In any case, the beam components are subject to the influence ofthe dynamic convergence coil 127 so that, irrespective of to which partof the target electrode they are deflected by the yoke 118, allcomponents converge substantially at the same point.

Again, in this form of the invention, representative circuit details ofthe control voltage generator 128 by which the dynamic convergence coil127 is energized, are shown by way of example only. The pulses derivedfrom the synchronizing signal channel 45 at the vertical deflectionfrequency are impressed by capacitor 129 upon a resistive-capacitivenetwork consisting of series resistors 132, 133 and 134 and shuntcapacitors 13S and 136. The output terminal of this network is coupledto the control grid 137 of a combining electron tube 138. The cathode ofthis tube is connected to ground through a series arrangement ofvariable resistor 139 and fixed resistor 140. The fixed resistor isbypassed by a capacitor 141. The screen grid 142 is connected to apositive potential point +B through a resistor 143 and is bypassed toground by a capacitor 144.

The pulses derived from the synchronizing signal channel 45 as thehorizontal deflecting frequency are impressed by the capacitor 131 upona grounded potentiometer 145. Preferably, these pulses have parabolicwave forms. As previously described, they may be derived from thebooster-damper storage capacitor. The potentiometer 145 is coupled by acapacitor 146 to the control grid 137 of the tube 138. A grid-leakresistor 147 also is provided.

Space current for the tube 138 is provided by means of the connection ofthe dynamic convergence coil 127 between the source of positivepotential +8 and the anode of the tube.

The described apparatus forming the convergence control generator 128functions to convert the pulses derived at horizontal and verticaldeflection frequencies from the synchronizing signal channel 45 into acomposite voltage for energizing the dynamic convergence coil 127. Inview of the fact that the composite voltage is derived from thehorizontal and vertical deflection voltage sources, it is seen that theenergization of the coil 127 varies as a function of the deflection ofthe electron beam components over the target electrode of the kinescope115.

This invention provides convergence of a plurality of electron beamcomponents substantially at all points in the plane of a targetelectrode. This result is achieved even though the beam componentsemanate from different points spaced from the central or otherlongitudinal axis of a cathode ray tube. Electron beam components ofthis character are particularly useful in multi-color kinescopes forcolor television systems.

Also, the electron beam components may be produced by a plurality ofelectron guns or by a single gun. The electronic energy produced by thegun or guns may be continuous or pulsating.

Furthermore, deflection of the electron beam components to form atelevision or other raster at the target electrode may be eitherelectromagnetic or electrostatic. The dynamic convergence of theelectron beam components may be either electromagnetic or electrostatic.The deflection and dynamic convergence systems may both be of the samekind or not, as desired.

The nature of the invention may be determined from the foregoingdisclosure of several embodiments thereof. The scope of the invention isset forth in the following claims.

What is claimed is:

1. In a cathode ray tube having a target electrode, an electronbeam-controlling system comprising, means for generating a plurality ofmutually spaced electron beam components the effective points of originof which being at different respective distances from substantially allpoints on said target electrode, a beam-deflecting system disposed in aregion spaced from said target electrode, means for directing saidelectron beam components into said deflecting region in such a mannerthat they are differently affected by said beam-deflecting system, meansfor variably energizing said deflecting system to cause all of said beamcomponents to scan a predetermined raster on said target electrode andan electron-optical system adjacent the paths of said beam componentsand energizable as a function of said beam deflection to maintainpredetermined relative positions of said beam components at all pointsof said raster.

2. In a cathode ray tube having a target electrode, an electronbeam-controlling system comprising, means for generating a plurality ofmutually spaced electron beam components the effective points of originof which being at different respective distances from substantially allpoint-s on said target electrode, a beam-deflecting system disposed in aregion spaced from said target electrode, means for directing saidelectron beam components into said deflecting region in mutually spacedrelationship, means for variably energizing said deflecting system tocause all of said beam components to scan a predetermined raster on saidtarget electrode, an electron-optical system adjacent the paths of saidbeam components and energizable to maintain predetermined relativepositions of said beam components at all points of said raster, andmeans for variably energizing said electron-optical system as a functionof the variable energization of said deflecting system.

3. In a cathode ray tube having a substantially flat target electrode,means for generating a plurality of mutually spaced electron beamcomponents, an electron beam-controlling system comprising abeam-deflecting system disposed in a region spaced from the plane ofsaid target electrode, means for directing said electron beam componentsinto said deflecting region at different angles, means producinghorizontal and vertical beam-deflecting energy components for variablyenergizing said deflecting system to cause all of said angular beamcomponents to scan a predetermined raster on said target electrode, anelectronoptical system adjacent the paths of said beam components andenergizable to converge all of said beam components at all points ofsaid raster, means varying as a function of said horizontalbeam-deflecting component for energizing said electron-optical system tocontrol said beam components vertically, and means varying as a functionof said vertical beam-deflecting component for additionally encrgizingsaid electron-optical system to control said beam componentshorizontally.

4. An electron beam-controlling system as defined in claim 1, whereinone of said beam-deflecting and electronoptical systems iselectromagnetic and the other is electrostatic.

5. An electron beam-controlling system as defined in claim 1, whereinboth of said beam-deflecting and electronoptical systems areelectromagnetic.

6. An electron beam-controlling system as defined in claim 1, whereinsaid beam-deflecting system is electromagnetic and said electron-opticalsystem is electrostatic.

7. An electron beam-controlling system as defined in claim 1, whereinsaid cathode ray tube also includes a plurality of electron guns forproducing said respective electron beam components.

8. An electron beam-controlling system as defined in l 13 claim1,.whereinsaid cathode ray tubealsonincludesya single electron gun forproducing all of said electronbearn components.

i 9. In a color .kinescope ,ha-ving a luminescent screen including amultiplicity of groups of sub-elementaldi- 1 ,mensioned phosphor areascapable respectively of producing differently colored light whenelectronically excited, a

masking electrode disposed in spaced relationship to said luminescentscreen, said masking electrode having an ,-ap erture for each of saidgroups of phosphor areas, means for developing and directing a pluralityof electronabeam components toward said luminescent screen through .suc-

.cessive apertures of said masking electrode to selectively excite said-difierent color-producing phosphor .areas, means for variablydeflecting all of saidbeamcomponents to scan a predetermined raster atsaid masking electrode, said electron beam components having non-uniformcharacteristics whereby theyare diverslyaflected bysaid deflection, anelectron-optical system disposed adjacentthe paths of said beamcomponents, andmeans for. variably energizing said electron-opticalsystem as a functionfof the varlable electronbeam deflection .toconverge all of said beam components at all points of.the.rasterscanned.at

, said masking electrode.

.10. In a color kinescope havinga substantially fiat.

luminescent screen including a multiplicity of groups of subelementaldimensionedphosphor areas capable respectively of producing differentlycolored lighLwhenelectronically excited, a masking electrode disposed inspaced relationship to and substantially parallel to saidfluminescentscreen, said masking electrode having ,anaperture for and in substantialregister with each of said groups of phosphor areas, means fordeveloping and directing electron beam components toward saidluminescent screen maskingelectrode to selectively excite said differentcolorproducing ,phosphorareas, a beam-deflecting systemj dis- [posed ina region betweensaid beam-developingmeans and said masking electrode,means for variably energizing said deflecting system to cause all ofsaid beam-components substantially concurrently to scan a predeterminedraster at said masking electrode, an.electron-opticalsystem disposedadjacent the paths of said beam components be tween said beam-developingmeans and said deflecting System, and means for variablyenergizing saidelectronoptical system as a function of thevariableenergization of saiddeflecting system-to converge all of ,saidjbearn components at allpoints of the raster scanned at said masking electrode.

11. In a color ,kinescope having a luminescentscreen including amultiplicity of groups of sub-elemental dimenfsioned phosphor areascapable respectively of pro jdu eing differently colored light whenelectronically .excitedQa masking electrode disposed in spacedrelationship togsaid luminescent screen, said masking electrode having.an

aperture for each .of said groups of phosphor areas, means including aplurality of electronguns respectively for fdeveloping and directing apluralityof mutuallyispa'ced electron beam components toward saidluminescent screen through successive apertures of said maskingelectrode sioned phosphor areas capable respectively of producingdifferently colored light'when electronically excited, a

masking electrode disposed in spaced relationship to said luminescentscreen, said masking electrode 'h'avin'g...an

from dilferent angles through successiveapertures of said I mutuallyspaced-electron beam-components directed to ward said luminescent screenthrough successive aper turesflof said masking electrode .to selectivelyexcite said ditferentrcolor-producing phosphor areas, means forvariablygdeflecting .all of saidnbeam components to scan a-predetermined .rasterat said. .rnaskingelectrode, an electromagneticelectron-optical systemldisposed :adjacent :the

paths of said .beam.components,..and means. for variably energizing said.electromoptical systemas .a. function :of

vthe variable electrongbeam deflection to converge ,allcof said beamcomponents .at all points of the .rasternscanned at said maskingelectrode.

13. In a color television irnagevreproducing system in- ,.cluding acathode ray .tube. having :a. luminescentqscreen .of a type producinglight; .of. the component colors of an image when impinged by electronbeam .componentsuap- ,proaching it.from,,different..angles and deflected.to v scan .avraster at said, screen, ,apparatus forcontrolling theconvergence .ofsaid beam. components in a planeinthe vicinity ofsaid..screen,.saidiapparatus comprising,,,means producing a ,plurality.,of .electronbeam components traversing pre-defiect'iontpaths.thatnarerspaced respectively about theflongitudinal laxisiof. the tube,meanslocated adjacent,saidlpre-deflectionfbeam paths and energizable toeffect. said beam convergence, .and means ,energizing ,one of, saidtwofirst mentionedimeans as a .functionof saidbeam deflection to varysaidheanrconvergence .angle in a manner to maintainjbeam convergence in saidplaneat ,all points 0t the scanned raster.

.14. In .a ca'thode .ray tube intage-reproducing system wherein; aplurality, of .electron beams, traverse predeflec- ,tion paths that .arespaced-.respectively aboutthelongitudinalaxis of thetube, electronbeam-controlling system comprising, apparatus energizable.to.angularly,deflect said beams both horizontally; andverticallyltoscana raster. in a predetermined ,plane, electron beamconvergence .ap-

paratuslocated adjacentrsaid predeflectionpaths and .energiaabletoinflueneesaidbeams so .as to effect substantial convergence. of,saidfbearns .at all of the scanned raster, and convergence control rneanscoupled to said deflection apparatitsso as to derive energy therefrom,said control means also being coupledto.saidconvergence apparatusso as,toenergizeit,as a..function of said angular beam deflection.

.15. Electron beam-controlling system was defined in claim l4 wherein,said covergence controlmeans is coupled'to saidhorizontal beamdeflection apparatus to .de- "rive energy at horizontal deflectionfrequency.

to. Electron beam-controlling system as defined -in claim 1,4'wherein,said convergence control means is coupled to both said horizonta'l .andvertical beam deflection apparatus. .to derive energy at both horizontal.and vertical-deflection frequencies.

hi7. In a color television receiver the combinationineluding: a cathoderay image-reproducing tube having ,a'luminescent screen of .a characterto producelight of component colors of an image when impinged byelectron beam components, and means for producing a plurality, ofelectron beam components respectively having difler- .entcharacteristics; deflection apparatus, for angularly idefleetingsaidplurality of heamcomponentsto scana raster of predeterminedconfiguration on said;screen; the respective characteristics and mutualrelationship imposition of said 'screen and said "electron "beamproducing means being such that the positional relationships of saidbeam components 'at said screen are notconstant at all "points 'o'f'said'scanned'raster; means located adjacent thepaths of said plurality ofbeam cornponentsand'energizable-to produce a desired positionalrelationship of said .beam components at;said screen; andscmeans.for'energizingzone 'zof said'riwozproducinguneanssas .a function :of.saidrbeam 15 deflection angle in such a manner as to maintain saiddesired positional relationship of said beam components at said screenat all points of said scanned raster.

18. In a color television receiver, the combination including: a cathoderay image-reproducing tube having a luminescent screen of a character toproduce light of component colors of an image when impinged by electronbeam components, and means for producing a plurality of electron beamcomponents respectively having different characteristics; means forangularly deflecting said plurality of beam components to scan a rasterof predetermined configuration on said screen; the respectivecharacteristics and mutual relationship in position of said screen andsaid electron beam producing means being such that the positionalrelationship of said beam components at said screen are not constant atall points of said scanned raster; means located adjacent the paths ofsaid plurality of beam components and energizable to produce a desiredpositional relationship of said beam components at said screen; andmeans for energizing said last-named means as a function of said beamdeflection angle in such a manner as to maintain said desired positionalrelationship of said beam components at said screen at all points ofsaid scanned raster.

19. In a color television receiver, the combination including: a cathoderay image-reproducing tube having a luminescent screen of a character toproduce light of component colors of an image when impinged by electronbeam components, means for producing a plurality of electron beamcomponents respectively having difierent characteristics, and means forfocussing said individual beam components substantially at saidluminescent screen; means for angularly deflecting said plurality ofbeam components to scan a raster of predetermined configuration on saidscreen; the respective characteristics and mutual relationship inposition of said screen and said electron beam producing means beingsuch that the positional relationship of said beam components at saidscreen are not constant at all points of said scanned raster; andelectron-optical means located adjacent the paths of said plurality ofbeam components and having an effect upon said beam components whichvaries as a function of said beam deflection angle in such a manner asto maintain said desired positional relationship of said beam componentsat said screen at all points of said scanned raster.

20. In a color television receiver, the combination including: a cathoderay image-reproducing tube having a luminescent screen of a character toproduce light of component colors of an image when impinged by electronbeam components, and means for producing a plurality of mutually spacedelectron beam components the effective points of origin of which beingat different respective distances from substantially all points on saidluminescent screen; means located between said effectwo points of beamcomponent origin and said screen for angularly deflecting said pluralityof beam components to scan a raster of predetermined configuration onsaid screen; and electron-optical means located adjacent the paths ofsaid plurality of beam components in a region between said eifectivepoints of beam component origin and said screen and having a directingeffect upon said beam components which varies as a function of said beamdeflection angle in such a manner as to produce a desired reduced mutualspacing of said beam components at all points of said scanned raster.

21. In a color television receiver, the combination including: a cathoderay image-reproducing tube having a luminescent screen of a character toproduce light of component colors of an image when impinged by electronbeam components, and means for producing a plurality of mutually spacedelectron beam components the effective points of origin of which beingat different respective distances from substantially all points on saidluminescent screen; means including field producing apparatus havingbeam entrance and beam exit portions for deflecting said plurality ofbeam components to scan a raster of predetermined configuration on saidscreen; and electron-optical means located between said effective pointsof beam component origin and the beam exit portion of said deflectingfield producing apparatus and having a directing effect upon said beamcomponents which varies with said beam deflection in such a manner as toeffectively eliminate the mutual spacing of said beam components at allpoints of said scanned raster.

22. In a cathode ray tube image-reproducing system, the combinationincluding: means for generating a plurality of electron beam components;a target electrode; deflection apparatus for angularly deflecting saidbeam components in a manner to cause them to scan a raster ofpredetermined configuration on said target electrode; said beamcomponent generating means and said target electrode having suchrespective characteristics and being so related in position to oneanother that normally the positional relationships of said electron beamcomponents at said target electrode are not constant at all points ofsaid raster; means located adjacent the paths of said plurality of beamcomponents and energizable to produce a desired positional relationshipof said beam components at said target electrode; and means derivingenergy from said deflection apparatus for energizing said last-namedmeans as a function of said beam deflection angle in such a manner as tomaintain said desired positional relationship of said beam components atsaid target electrode at all points of said scanned raster.

23. In a color television receiver, the combination including: a cathoderay image-reproducing tube having a luminescent screen of a character toproduce light of component colors of an image when impinged by electronbeam components, and means for producing a plurality of mutually spacedelectron beam components the effective points of origin of which beingat difierent respective distances from substantially all points on saidluminescent screen; horizontal and vertical deflection apparatus forangularly deflecting said beam components both horizontally andvertically to scan a raster of predetermined configuration on saidscreen; electron-optical means located adjacent the paths of saidelectron beam components and energizable to have a directing eifect uponsaid beam components so as to produce a desired positional relationshipof said beam components at said screen; and means deriving energy fromsaid horizontal deflection apparatus for energizing saidelectron-optical means as a function of said horizontal beam deflectionangle in such a manner as to maintain said desired positionalrelationship of said beam components at said screen at all points ofsaid scanned raster.

24. In a color television receiver, the combination including: a cathoderay image-reproducing tube having a luminescent screen of a character toproduce light of component colors of an image when impinged by electronbeam components, and means for producing a plurality of mutually spacedelectron beam components the effective points of origin of which beingat different respective distances from substantially all points on saidluminescent screen; horizontal and vertical deflection apparatus forangularly deflecting said beam components both horizontally andvertically to scan a raster of predetermined configuration on saidscreen; electron-optical means located adjacent the paths of saidelectron beam components and energizable to have a directing effect uponsaid beam components so as to produce a desired positional relationshipof said beam components at said screen; and means deriving energy fromsaid horizontal and vertical deflection apparatus for energizing saidelectron-optical means as respective functions of said horizontal andvertical beam deflection angles in such a manncr as to maintain saiddesired positional relationship of References Cited in the file of thispatent UNITED STATES PATENTS Keyston et'al. July 5, 1938 Farnsworth Dec.13, 1938 Bahring Dec. 10, 1940 Witherby et a1. Sept. 14, 1948 18Harrison Oct. 30, 1951 Green Dec. 25, 1951 Schroeder Dec. 25, 1951Schroeder May 6, 1952 Bull Oct. 7, 1952 FOREIGN PATENTS France June 6,1941

